1. Field of the Invention
The invention is related to computers and computer systems, and in particular, to computer system management.
2. Background Information
Many computer systems today communicate remotely via a serial modem connected to the computer system via a serial port. A management controller can access a communication device, such as a modem, through the serial port such that the computer system shares the modem with the management controller. A remote system can initiate communication with the management controller via the modem. The management controller can essentially answer the phone so that the remote system can establish a dialogue with the management controller. When the remote system has finished communicating with the management controller, the remote system can switch the modem to the computer system and then establish a dialogue with the computer system.
The computer system and the management controller cannot both use the modem simultaneously. To accommodate this, the modem is switched between use by the system motherboard""s serial controller and the management controller""s serial controller using circuitry for switching the signals to the serial connector. This is sometimes referred to as xe2x80x9cserial port switchingxe2x80x9d or xe2x80x9cserial port sharing.xe2x80x9d
There is a transition today towards greater Universal Serial Bus use. A Universal Serial Bus (xe2x80x9cUSBxe2x80x9d or xe2x80x9cBusxe2x80x9d) is a well-known cable bus that supports data exchange between a computer system""s host processor and a wide range of simultaneously accessible peripheral devices, e.g., printers, mice, joysticks, scanners, keyboards, telephones, etc. The attached peripherals share the Bus, which allows the peripheral devices to be attached, configured, used, and detached while the host processor and other peripheral devices are in operation.
One characteristic of USB is that it is a polled bus that periodically polls each peripheral device, to determine whether it is attached, for example. Thus if the modem is switched away from the host computer system""s use, the software resident on the host computer system that interacts with the USB system software interprets this as a xe2x80x9cdetachmentxe2x80x9d of the modem from the computer system. Moreover, when the modem switches back to the computer system, the computer system""s software must xe2x80x9cattachxe2x80x9d the modem as though the modem were a newly attached device.